斜带石斑鱼(♀)×鞍带石斑鱼(♂)杂交子代仔、稚鱼的异速生长

Allometric growth of hybrid grouper(Epinephelus coioides ♀×E. lanceolatus ♂) larvae and juveniles

应用实验生态学的方法研究斜带石斑鱼（Epinephelus coioides）（♀）×鞍带石斑鱼（E. lanceolatus）（♂）杂交子代（青龙斑）仔、稚鱼阶段的生长模式。利用Q-Capture Pro 6软件对仔、稚鱼（0~28日龄）的全长、肛前长、体高、头长、眼径、口径、第二背鳍棘、腹鳍棘、胸鳍、臀鳍和尾鳍等11个可量性状进行拍照和测量。研究表明青龙斑全长的生长可分为3个阶段，不同阶段生长速率存在显著差异（＜0.05）。各功能器官均表现为异速生长。在11个可量性状中，肛前长为等速生长，头长和体高的生长由正异速生长分别转变为等速生长和负异速生长；头部器官（口径和眼径）生长在20~22日龄时出现拐点，拐点后分别转变为等速生长和负异速生长；运动器官在拐点前均为正异速生长，除臀鳍外，其他各鳍的生长均存在不同的拐点。通过对青龙斑仔、稚鱼异速生长的研究，发现在早期发育过程中，有关摄食、感觉、运动等功能器官得到优先发育。在人工繁殖苗种的培育中，可根据青龙斑重要器官发育的优先性，创造有利的外部环境，提高苗种的成活率。

We evaluated the pattern of allometric growth in hybrid Qinglong grouper [Epinephelus coioides （♀）×E. lanceolatus （♂）] during the larval and juvenile stages. We measured the total length, pre-anal length, trunk height, head length, eye diameter, mouth width, the second dorsal fin spine, pelvic fin spine, pectoral fin, anal fin, and tail fin of Qinglong grouper （from hatch to 28 d） and captured images of each individual using Q-Capture Pro 6. The average total length of newly hatched larvae was （1.62＆#177;0.26） mm. After 28 d, the total length of juveniles was （16.58＆#177;1.09） mm at a water temperature of （30＆#177;1）℃ and a salinity of 28＆#177;1. The growth in total length of Qinglong grouper was divided into three stages. The growth rate during the first, second, and third stages was 0.11 mm/d （from hatch to 7 d）, 0.37 mm/d （from 8 to 21 d）, and 1.51 mm/d（22 d afterwards）, respectively. There was a significant difference in the growth rate between larval and juvenile stages （〈0.05）. Some of the organs exhibited allometric growth in early ontogeny. Head length and trunk height were positively allometric up to the inflexion point, then switched to isometric and negatively allometric, respectively. Pre-anal length was characterized by isometric growth and had no inflexion point during the larval and juvenile stages. The growth in the head （inflexion point at 21-22 d） and sensory organs （inflexion point at 20-21 d） was positive up to the inflexion point, then became isometric and negatively allometric, respectively. The second dorsal fin spine and pelvic fin spine exhibited strong positive allometry at first, before becoming negatively al-lometric. The inflexion point of the second dorsal fin spine was between 20 and 21 d, whereas that of the pelvic fin spine was at 17 d. The second dorsal fin spine and pelvic fin spine reached a maximum at 24 d. From hatch to day 26, pectoral and tail fin growth was positively allometric, and their inflexion points were between 14 and 15 d, and 22 and 23 d, respectively. Anal fin growth was positively allometric and had no inflexion point. This pattern of growth results in rapid improvement in swimming ability, thereby allowing individuals to search for food and escape predators. Our results suggest that the organs involved in feeding, sensing, and swimming developed most rapidly during the early de-velopmental stages in Qinglong grouper. To increase the survival rate of Qinglong grouper during early life stages, it is critical to provide environmental conditions that account for the priority order of organ development.